This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. xc2xa7119 from an application entitled COVER STRUCTURE OF HARD DISK DRIVE earlier filed in the Korean Industrial Property Office on Nov. 17, 1998 and there duly assigned Ser. No. 98-49257.
1. Field of the Invention
The present invention relates generally to a storage device, and in particular, to a cover structure of a hard disk drive (HDD), which can minimize internal noises and vibrations.
2. Description of the Related Art
A hard disk drive, which is widely used for an auxiliary storage of a computer, is divided into a printed circuit board assembly (PCBA) and a head disk assembly (HDA). The PCBA includes a PCB on which various electric and electronic devices are mounted. The HDA includes major mechanical devices such as head, disk, voice coil motor (VCM), actuator, etc., and minor circuit devices.
In such a hard disk drive, internal noises are generated from the mechanical devices such as the spindle motor, disk, head, VCM, arm, etc. Such noise sources are surrounded by a cover and a base, so that the cover and base should be designed in full consideration of the noises and vibrations. Particularly, in most cases, the cover is thinner than the base, so that the noises may be transmitted (or permeate) through the cover. Further, vibrations originating from the base may be transferred to the cover, causing a new noise source.
Examples of the contemporary art of devices to dampen noise from hard disk drives are seen in the following U.S. patents. U.S. Pat. No. 5,825,585, to Hatam-Tabrizi, entitled Laterally Constrained And Damped Mount For A Hard Disk Drive, describes an assembly that couples a spindle shaft to the cover of a hard disk drive, for dampening vibration loads and for reducing the acoustic noise from the drive to the enclosure.
U.S. Pat. No. 5,587,855, to Kim, entitled Supporting Device For Minimizing Vibration, Noise And External Impact Of A Hard Disk Drive, describes a supporting device having a plate fixed to the shaft of a spindle motor and a damper made of a soft elastomer on the upper portion of the plate, for damping vibration energy.
U.S. Pat. Nos. 5,510,954 and 5,596,483, to Wyler, entitled Silent Disk Drive Assembly and Silent Air Cooled Computer Having A Hard Disk Drive With An Acoustic Shield And A Heat Sink Arranged Exterior To The Drive, respectively, describe an acoustically shielded hard disk drive having a sound absorption layer surrounding the disk drive assembly. An embodiment in which the disk drive is enveloped in sound proofing material and housed in an airtight one-eighth inch acrylic housing is described. In addition, a fluid containing pouch and a metal bracket surround the hard disk drive inside the sound proofing material. This is an elaborate and expensive arrangement for providing soundproofing.
U.S. Pat. No. 5,021,905, to Sleger, entitled Disk Drive Enclosure For Minimizing Stresses And A Vibration Damping Seal Therefor, describes a disk drive in which the base and cover are connected with a peripheral gap which is sealed by means of a viscoelastic tape. The tape seal provides resonant damping in the drive structure. The ability of this arrangement to block sound passing through the cover is probably limited, however.
U.S. Pat. No. 5,538,774, to Landin et al., entitled Internally Damped Rotatable Storage Article, provides a method for dampening vibration of a rotatable storage article such as a hard disk by introducing a viscoelastic material as an inner layer of the article.
U.S. Pat. No. 5,965,249, to Sutton et al., entitled Vibration Damping Composite Material, describes a material which incorporates mechanically unstable materials within porous constructs. The patent illustrates a hard disk drive having the material for vibration damping of noise from the drive. As illustrated, a layer of the damping material is adhered to the cover of the disk drive and a constraining layer using an adhesive on each side. Also, a layer of the material may be applied to the top of the voice coil motor plates to dampen noise from the voice coil motor.
To solve the noise problems, one improved cover has a cover damper mounted thereon to reduce the internal noises and vibrations. For the cover damper, stainless steel is typically used, the rigidity of which is higher by about 10 times that of aluminum used for the cover.
Recently, to reduce the manufacturing cost and to simplify the manufacturing process, internal devices such as spindle motor and VCM have been modified. In particular, a process for manufacturing the cover has also been modified. Although modification of the spindle motor and VCM may contribute to reduction in noises and vibrations, thereby increasing performance of the hard disk drive, modification of the cover manufacturing process to thin-plate molding will reduce the thickness of the cover, causing an increase in noises and vibrations. Accordingly, there is a demand for a thin hard disk drive cover having an increased sound shielding capability in terms of noises and vibrations.
It is therefore an object of the present invention to provide an improved hard disk drive.
It is also an object of the invention to provide an improved structure of the cover of a hard disk drive.
It is a further object of the present invention to provide a cover of a hard disk drive which suppresses noise and vibration in the hard disk drive.
It is a yet further object of the invention to provide a cover of a hard disk drive which is thin.
To achieve the above objects, a hard disk drive according to an embodiment of the present invention includes a cover, a cover damper mounted on the cover, and an air layer provided between the cover and the cover damper.